Water treatment system and method using high pressure advanced oxidation process with unreacted ozone reusing

ABSTRACT

A water treatment system using a high pressure advanced oxidation process with unreacted ozone reusing is disclosed, which are able to increase a decomposition speed of a pollutant by reusing a high pressure advanced oxidation process which uses an ozone and photocatalyst and a photo-oxidation reaction of a ultraviolet ray. The capacity of the expensive ozone generator can be reduced as compared to the conventional advanced oxidation process which uses a large capacity ozone generator in which almost ozone is discharged into the air. In addition, it is possible to decrease the load of the off-gas ozone removing apparatus for removing the off-gas ozone which is discharged into the air.

RELATED APPLICATIONS

This application is a 371 application of International Application No.PCT/KR2007/004176, filed Aug. 30, 2007, which is incorporated herein byreference in its entirety.

TECHNICAL FIELD

The present invention relates to a water treatment system using a highpressure advanced oxidation process with unreacted ozone reusing, and inparticular to a water treatment system using a high pressure advancedoxidation process with unreacted ozone reusing and a method of the samewhich are able to increase a decomposition speed of a pollutant byreusing a high pressure advanced oxidation process with unreacted ozonereusing and photocatalyst and a photo-oxidation reaction of aultraviolet ray.

BACKGROUND ART

A water treatment method using an advanced oxidation process (AOP) isdirected to a technology which generates an OH radical (OH°, Hydroxyradical) having a strong sanitization and oxidizing power as anintermediate material by using an oxidation agent such as ozone or H₂O₂or by scanning a ultraviolet rat to the oxidation agent for therebyoxidizing and decomposing an organic pollutant in a waste water. Theabove water treatment method is an advanced technology which is used todecompose a undecomposable substance such as a synthetic washing agent,agricultural chemical, etc. which are not well decomposed by a commontreatment method and is used to decompose a high concentration pollutantfor a short time period. In recent years, as an environment pollutionbecomes a serious problem, and a new material, which cannot bedecomposed by a common treatment method, is developed, a new technologyis needed with respect to a waste treatment method which has anexcellent process efficiency as a lot of undecomposable substance isinputted into a waste water. In addition, according to the amended lawin the Korean law, it became a duty matter that a heavy water facilityis installed in an architecture having a certain dimension. In case of acity building which is hard to adapt a biochemical treatment method, andin case of a conventional factory which is hard to increase a treatmentcapacity of a waste water, and in case that a lot of waste water shouldbe treated in a limited treatment space, the application of a watertreatment method using an advanced oxidation is widened, which has ahigh treatment efficiency of a waste water and is able to treat a lot ofwater for a short time without bad smell in a small area.

In recent years, various trials are conducted for enhancing adecomposition efficiency of an advanced oxidation process. A multiplereaction tub may be installed so as to enhance a contact surface area ofozone. According to a DOF (Dissolved Ozone Flotation) method, ozone iscompressed using a compressor so as to enhance solubility and isinputted into a waste water which is pressurized with a high pressureand is discharged to a waste water with a normal pressure for therebyforming ozone foams and floating the same. The pollutant and micro ozoneare reacted with each other. According to the DOF, it is possible toobtain a less size foam and a larger size surface area as compared towhen foam is generated by means of a conventional ejector. So, it ispossible to increase decomposition reaction efficiency as a contactefficiency of ozone increases.

In addition, there is a method for inducing a decomposition reaction ofozone in an area near a lamp in consideration with a characteristic ofan ultraviolet ray (254 nm) having a low water penetration power as anultraviolet ray is scanned so as to increase a decomposition efficiencyof ozone, a porous plate is installed near an ultraviolet lamp, andozone passes through near a lamp. In the above operation, it is expectedthat a decomposition reaction efficiency is enhanced based on an OHradical generated as a photocatalyst scanned by an ultraviolet raydecomposes ozone by coating a photocatalyst on the porous plate. Thewater treatment apparatus and method using an advanced oxidation processis disclosed in the Korean patent laid-open number 109288, the patentregistration number 289275 and the patent registration number 541573.

However, the above patents have the problems. Namely, the Korean patentregistration number 109288 and the patent registration number 289275disclose the DOF in which the ozone is pressurized using a compressor soas to purify waste water, and the pressurized ozone is inputted into thewaste water which was pressurized using a pump and is dissolved, and isinputted into waste water under normal pressure for thereby generating amicro foam ozone and increasing the contact surface. In the abovemethod, it is possible to enhance a decomposition reaction efficiency asthe contact surface area increases with respect to the pollutant withsmall size foams as compared to the floating method by means of anejector having relatively large foams, but the amount of the ozone to bedissolved under water under the normal pressure is very limited, so thatalmost ozone inputted remain in a foam type, and the decompositionreaction of the ozone and pollutant is performed via a gas-liquidsurface. Therefore, the reaction speed is slow. As the pollutant foamsize decreases, the contact surface area increases, so that thedecomposition reaction speed may slightly increase. However, since theinputted ozone is fast floated above the water and escapes, the amountof the gaseous ozone is relatively less, so that there is a limit forenhancing the reaction efficiency.

The conventional advanced oxidation process is related with a technologywhich decreases the sizes of foams. The method for treating the wastewater based on the DOF which performs a reaction almost via a gas-liquidsurface is performed using an inherent oxidation power of ozone which isable to oxidize and decompose almost organic pollutants by enhancing acontact efficiency between ozone and pollutant. The above method isfaster than a biological decomposition method. In a lot of pollutants,the decomposition reaction speed is disadvantageously slow, and thevolume of the reaction apparatus disadvantageously decreases. There aresubstances which do not react, and a lot of undecomposable substancesuch as agricultural chemicals, synthetic washing agent, etc. may beinputted into sewage or waste water, so that there are limits fortreating the above water problems with only ozone.

So as to improve the disadvantages of the ozone, ozone is decomposed byconcurrently reacting oxidizing agent such as H₂O₂ and ultraviolet rayfor thereby creating an OH radical having a strong oxidizing power. As amethod for decomposing pollutants based on the created OH radical, thereis an advanced oxidation process such as ozone+H₂O₂, ozone+ultravioletray, ozone+photocatalyst+ultraviolet ray,ozone+photocatalyst+ultraviolet ray, ozone+ultrasonic wave, etc.

The Korean patent registration number 541573 discloses a method for anadvanced oxidation process which uses ozone+photocatalyst+ultravioletray in which ozone is inputted via a lower side of the reactor and isdispersed via a porous plate formed at a surrounding portion of anultraviolet lamp and is decomposed, so that a decomposition reaction isperformed based on a photocatalyst coated on the surface of the poroushole. Since the inputted ozone is present in a foam state, as the inputamount of ozone increases, the amount of foams increases for therebyretarding the irradiation of ultraviolet ray, and the size of ozone foamincreases, so that the contact efficiency with the pollutant decreases,and the creating amount of the OH radical generated based on thedecrease of the oxidation reaction and by means of a reaction of theultraviolet ray. In the above patents, there is provided a watertreatment apparatus which has a porous plate coated with a photocatalystthrough which the ultraviolet lamp passes so as to enhance a reactionbetween the ozone and the ultraviolet ray. However, the number of theporous plate is limited for the reason of the pressure loss. It isimpossible to increase the creation of the OH radical based on anultraviolet ray decomposition reaction and a photocatalyst reactionowing to the retardation of the ultraviolet ray scanning due to theozone foams. As a result, the surface area of the photocatalyst coatingcannot increase owing to the increasing pressure loss by means of theinstalled porous plate, so that there is a limit in the pressescapacity. Namely, there is a limit for enhancing the decompositionreaction efficiency since the solubility of the ozone inputted in a foamshape, and the transmission of the ultraviolet is interfered.

In the advanced oxidation process using a conventional DOF, the ozone ispressurized to a high level using the compressor, and the waste water ispressurized using a pressurizing pump, and a high pressure ozone isinputted into the waste water and is dissolved and then is dischargedwith a normal pressure, so that a micro size ozone foam is generated andis floated upward for thereby along the floating substance to move upand react with the pollutant, whereby the pollutant are removed. Thewater treatment method based on the DAF (Dissolved Air Flotation) andthe DOF (Dissolved Ozone Flotation) are disclosed in the Korean patentlaid-open number 10-2006-0026698, the Korean patent laid-open number10-2005-0109288, the Korean patent registration number 0321800, and theKorean patent registration number 0420561. In the floating substance andpollutant removing method using the micro size foam type air or ozonefloatation, the waste water is sucked and compressed by means of thepressure pump, and the ozone generated by the air and ozone generator iscompressed by means of the compressor and is forcibly inputted into ahigh pressure waste water and is dissolved. A method of using anexclusive pump, for example, a DAF pump is considered.

In the air flotation method, the floating substance contacts with microfoams and is floated upward for thereby removing the same. A lot of airis dissolved with a high pressure so as to enhance the efficiency of theair floatation method and is inputted into a waste water of a normalpressure for thereby forming micro foams. In a method for enhancing afloating substance removing efficiency, a specially designed DAFexclusive pump may be used, and a high pressure air compressed using thecompressor is mixed and dissolved by means of a high pressure wastewater pressurized by the pressurizing pump and is inputted into afloatation tub. However, in this method, an air compression compressoror an exclusive DAF pump is disadvantageously needed.

In the conventional advanced oxidation process, since unreacted ozone isproperly not used, but is just discharged into the air or it isdecomposed using a decomposition apparatus and is discharged, the useefficiency of the ozone is very low. Since an expensive ozone generatoris used, and a cost is increased since it is needed to increase acapacity of a unreacted ozone decomposition apparatus. The apparatusneeded for an advanced oxidation process should be big so as to increasethe contact area needed for enhancing a decomposition reactionefficiency of a pollutant, so that an installation and operation costincreases.

In addition, almost ozone is not properly used since a technologyrelated with a pollutant removing process using a conventional advancedoxidation process adapts a unreliable treatment method with respect to aunreacted ozone. Namely, such ozone is directly discharged into the airor is simply decomposed using an off-gas ozone decomposition apparatus.Since an ozone generator is expensive, it is impossible to expect a highapplication of the ozone because the ozone is generated using anexpensive apparatus. An environmental problem may occur, and aninstallation cost and an operation cost are too high.

DISCLOSURE Technical Problem

Accordingly, it is an object to provide a waste water treatment methodusing a high pressure advanced oxidation process with unreacted ozonereusing which is able to increase a pollutant decomposition efficiencyand to minimize a unreacted ozone discharge amount through adecomposition efficiency maximization of an advanced oxidation processand a unreacted ozone reuse technology development. In addition, it ispossible to decrease a size of an expensive ozone generator and anadvanced oxidation process waste water treatment apparatus for therebydecreasing an installation cost and operation cost.

Technical Solution

To achieve the above objects, in a waste water treatment system andmethod using a high pressure advanced oxidation process with unreactedozone reusing according to the present invention, a lot of ozonegenerated by an ozone generator 70 is pressurized along with a wastewater with a high pressure, and is inputted into a high pressurephoto-oxidation decomposition apparatus 60 in a dissolved state with nofoam. A lot of dissolved ozone contacts with pollutants and is oxidizedand decomposed. Namely, an ozone decomposition reaction is performed bymeans of ultraviolet ray without ozone foams. A reaction for decomposingpollutant by means of an OH radical generated by a photo-oxidationreaction which decomposes ozone based on a photocatalyst reaction isproperly performed, so that a decomposition reaction speed of apollutant increases, and a reaction range increases, and the unreactedozone, which is not reacted in the above reaction, is inputted into asecondary pretreatment floatation tub 32 and a gas-liquid separationflotation tub 40 along with a high pressure reaction substance, so thatthe ozone is changed to a micro foam ozone foam which is floated upwardin the flotation tub and absorbs the flotation substance and floats onthe water. The ozone foams are transferred to a scum removing unit 31 dalong with the gas and are separated from the scum. So, the remainingozone is removed based on a first dissolved ozone/air flotationseparation method. The unreacted ozone collected at the upper sides ofthe secondary pretreatment flotation tub 32 and the gas-liquidseparation flotation tub 40 is pressurized with a high pressure alongwith the waste water and is inputted into the first pretreatmentflotation tub 31 in the secondary dissolved ozone/air flotationseparation method. Almost part of the ozone is removed through a seriesunreacted ozone reuse process which removes the floating substance andpollutant of the waste water. The remaining unreacted ozone is removedby means of the off-gas ozone removing apparatus 50 based on theenvironment standard and is discharged into the air. So, it is possibleto decrease the size of the off-gas ozone decomposition apparatus 50.The load of the pollutant inputted into the high pressurephoto-oxidation decomposition apparatus 60 using a unreacted ozone canbe decreased. The processing speed of the pollutant of the high pressurephoto-oxidation decomposition apparatus 60 may increase, so that a wastetreatment capacity can be enhanced. The capacity of the expensive ozonegenerator 50 can be decreased with the help of the above combinedfunctions. The installation cost and operation cost of the waste watertreatment apparatus can be decreased, and the advanced oxidation processwaste water treatment apparatus 100 can be made in a compact size.

In addition, in a waste water treatment system and method using a highpressure advanced oxidation process with unreacted ozone reusingaccording to the present invention, the source water pressurized bymeans of the photo-oxidation pressurizing is passed through the highpressure ozone reaction apparatus 90 and is inputted into the highpressure photo-oxidation reaction apparatus 60 and is water-treated bymeans of an ozone reaction before a photo-oxidation reaction for therebyenhancing a reaction efficiency based on the photo-oxidation.

In a waste water treatment system and method using a high pressureadvanced oxidation process with unreacted ozone reusing according to thepresent invention, an off-gas and an input water are contacted andpreliminarily heated in a common boiler for collecting waste heat, andthen the heat of the off-gas is removed. The pretreatment flotation tub30 and the gas-liquid separation flotation tub 40 are used forpreliminarily removing a floating substance and pollutant contained inthe waste water based on the dissolved ozone/air flotation separationmethod by means of a unreacted ozone. To achieve the above objects, thepretreatment flotation tub 30 comprises a first pretreatment flotationtub 31 in which a unreacted ozone is processed via the dissolvedozone/air flotation process with respect to the waste water of the wastewater storing tub 10 and is finally removed; and a second pretreatmentflotation tub 32 in which the high pressure reaction substance of thedischarge port 60 b of the high pressure photo-oxidation reactionapparatus 60 is inputted into the second pretreatment flotation tub 32having a waste water which was first treated based on the dissolvedozone/air flotation separation method in the first pretreatmentflotation tub 31 via the feedback line 69 for thereby second performingthe dissolved ozone/air flotation process. In the same method, in thegas-liquid separation flotation tub 40, a high pressure reactionsubstance is inputted into the low inlet 40 a of the gas-liquidseparation floatation tub 40 connected with the discharge port 60 b ofthe high pressure photo-oxidation reaction apparatus 60, so that thedissolved ozone/air flotation process is performed with respect to thewaste water treated via the above processes, and the unreacted ozone isreacted with the remaining pollutant in the treatment water for therebybeing removed.

In a waste water treatment system and method using a high pressureadvanced oxidation process with unreacted ozone reusing according to thepresent invention, the second pretreatment flotation tub 32 is connectedwith the feedback line 69 having the high pressure photo-oxidationdecomposition apparatus discharge port 60 b, the flow meter 69 a and theflow rate adjusting valve 69 b. Part or all of the high pressurereaction substance having the unreacted ozone is fed back into the lowinlet 32 c of the second pretreatment flotation tub 32 via the treatmentwater feedback line 69, and the unreacted ozone and pollutant areremoved based on the dissolved ozone/air flotation separation method.The reaction substance of the high pressure photo-oxidationdecomposition apparatus 60 is fed back into the lower side of the secondpretreatment flotation tub 32 and the high pressure photo-oxidationreaction apparatus 60, so that it is possible to adjust the load levelfor thereby minimizing the impacts of the second pretreatment flotationtub 32 and the high pressure photo-oxidation reaction apparatus 80 basedon the change of the concentration of the pollutant substance in thewaste water inputted via the above system. In addition, it is possibleto easily perform a first operation of the high pressure advancedoxidation process.

In a waste water treatment system and method using a high pressureadvanced oxidation process with unreacted ozone reusing according to thepresent invention, the ozone inputted into the waste water treatmentsystem 100 using a high pressure advanced oxidation process withunreacted ozone reusing is performed via the four steps, and almostozone is reacted with the pollutant and is removed, and the finallyremaining ozone is decomposed by means of the off-gas ozone removingapparatus 50 in compliance with the environment standard and isdischarged into the air.

In a waste water treatment system and method using a high pressureadvanced oxidation process with unreacted ozone reusing according to thepresent invention, the ozone supplied from the ozone generator 70 to thesuction port 65 a of the photo-oxidation pressurizing pump 65 and thetwice treated waste water supplied via the lower discharge port 39 ofthe second pretreatment flotation tub 32 are pressurized with abovethree atmosphere, so that the waste water inputted into the inlet 60 aof the high pressure photo-oxidation reaction apparatus 60 is used todecompose the pollutant based on the OH radical creation reaction viathe photo-oxidation decomposition reaction of the ozone or is removedvia the process in which the pollutant is decomposed based on theoxidation reaction of the dissolved ozone. Part of the high pressurereaction substance discharged via the discharge port 60 b of the highpressure photo-oxidation reaction apparatus 60 is connected from thetreatment water feedback line 69 to the lower input let 32 c of thesecond pretreatment flotation tub 32. The circulation line 63 connectedat the intermediate portion of the treatment water feedback line 69 isconnected to the inlet 60 a of the high pressure photo-oxidationreaction apparatus 60 via the circulation pump 63 a, the flow meter 63 band the flow rate adjusting valve 63 c, so that the high pressurereaction substance first reacted by means of the circulation pump 63 acirculates via the high pressure photo-oxidation decomposition apparatus60, whereby a series photo-oxidation decomposition reaction isrepeatedly performed. So, the ozone is removed in the course of furtherperforming the pollutant decomposition reaction in the first step. Whentreatment water containing a high pressure unreacted dissolved ozone viathe discharge port 60 b of the high pressure photo-oxidation reactionapparatus 60 is inputted into the lower input inlet 40 a of thegas-liquid separation flotation unit 40 via the flow meter 64 a and theflow rate adjusting valve 64 b, the ozone is created in the form of amicro unreacted ozone foam and contacts with the waste water filled inthe gas-liquid separation flotation tub 40 and floats upward and reactswith the remaining pollutant for thereby being removed based on thedissolved ozone/air flotation process in the second step. When thetreatment water having a high pressure unreacted dissolved ozone via thedischarge port 60 b of the high pressure photo-oxidation reactionapparatus 60 is fed back to the lower input inlet 32 c of the secondpretreatment flotation tub 32 via the photo-oxidation feedback line 69having the flow meter 69 a and the flow rate adjusting valve 69 b, microozone foams are floated, so that the pollutant contained in the firsttreated waste water and the unreacted ozone are removed based on thedissolved flotation process in the third step. The unreacted ozonecollected at the upper side of the gas-liquid separation flotation tub40 and supplied to the suction pot 35 a of the pretreatment flotationtub pressurizing pump 35 via the unreacted ozone reusing line 45 and theunreacted ozone collected at the upper side of the second pretreatmentflotation tub 32 and supplied to the suction port 35 a of thepretreatment flotation tub pressurizing pump 35 via the pretreatmentunreacted ozone reusing line 36 are pressurized with above threeatmosphere along with the waste water supplied from the waste waterstoring tub 10 for thereby dissolving the ozone and are inputted intothe lower input inlet 31 a of the first pretreatment flotation tub 31,so that the dissolved flotation process is performed for therebyremoving the ozone in the fourth step.

In a waste water treatment system and method using a high pressureadvanced oxidation process with unreacted ozone reusing according to thepresent invention, the ozone that the high pressure photo-oxidationreaction apparatus 60 received from the ozone generator 70 and the wastewater which was twice treated by the first and second pretreatmentflotation tubs 30 a and 30 b are pressurized so that the amount of theozone, which is inputted into the photo-oxidation pressurizing pump 65,is present in the foam state, is minimized, and the pressure and flowrate of the high pressure photo-oxidation reaction apparatus 60 areadjusted in such a manner that the revolution of the photo-oxidationpressurizing pump 65 is adjusted based on the flow rate determined bymeans of the pressure meter 64 b, the flow rate meter 64 a and the flowrate adjusting valve 64 c. According to the feedback system, part or allof the treatment water is fed back to the second pretreatment flotationtub 32 via the feedback line 69 connected with the discharge port 60 bof the high pressure photo-oxidation reaction apparatus 60 inconsideration with the load level of the high pressure photo-oxidationreaction apparatus 60 and the operation efficiency of the pretreatmentflotation tub 30. The lower inlet 60 a of the photo-oxidation reactionapparatus 60 is connected with the treatment water feedback line 69connected with the discharge port 60 b of the high pressurephoto-oxidation reaction apparatus 60 via the photo-oxidationcirculation pump 63, the flow meter 63 b, and the flow rate adjustingvalve 63 c, so that part or all of the high pressure reaction substanceis circulated for thereby adjusting the photo-oxidation reaction leveland the amount of the unreacted ozone, whereby the high pressurephoto-oxidation reaction is performed.

In a waste water treatment system and method using a high pressureadvanced oxidation process with unreacted ozone reusing according to thepresent invention, the photocatalyst coating supporter 67 filled in thehigh pressure photo-oxidation reaction apparatus 60 is made in a coilspring shape. Here, the diameter of the wire is 0.1˜0.5 mm, and thematerial is a metallic material such as stainless steel, titanium,aluminum, etc. The diameter of the coil spring 67 a is 5˜70 mm, and theshape of the coil spring 67 a is a hourglass shape. The pitch of thecoil spring 67 a is smaller than the diameter of the wire 67 b, and thepitches of the beginning and ending potions of the spring are near theneighboring pitches, so that the photocatalyst coating supporters 67 ofthe coil spring 67 a are not overlapped on the course of filling intothe high pressure photo-oxidation reaction apparatus 60 for therebyintensifying the filling. The wire surfaces 67 c may be sand-processedusing diamond sand and may be corroded using a chemical such as acid, sothat the wire surfaces 67 have protrusions for thereby enhancing anattaching power of the photocatalyst. The surface area of the coatedphotocatalyst can be enlarged.

In a waste water treatment system and method using a high pressureadvanced oxidation process with unreacted ozone reusing according to thepresent invention, the photocatalyst coating supporter 67 is made in acoil spring shape by winding the wire 67 b, and the wire surface 67 c istoughly processed for thereby increasing the surface area of the same,and titanium alkoxide is diluted in solvent and is coated. It isheat-treated at below 800° C. In the photocatalyst coating supporter 67made by stably coating the photocatalyst 67 d on the wire surface 67 c,ultraviolet rays are properly scanned into the space between the wires67 d of the coil spring 67 a, namely, between the pitches and betweenthe supporters 67 a, so that ultraviolet ray can reach at thephotocatalyst 67 d which is relatively far from the crystal tube 61having the ultraviolet lamp 62, so that the waste water havingpollutants can easily pass for thereby decreasing the pressure loss. Inthis case, it is possible to obtain a much wider surface area and a lesspressure loss as compared to when coating the photocatalyst on theporous plate. So, when the waste water is processed, the decompositionefficiency is high, and the treatment capacity can be increased.

In a waste water treatment system and method using a high pressureadvanced oxidation process with unreacted ozone reusing according to thepresent invention, when the photocatalyst coating supporter 67 in thetype of the coil spring 67 a is filled into the high pressurephoto-oxidation reaction apparatus, the photocatalyst coating supporter67 of the coil spring 67 a is compressed using an elastic force of thespring supporter and is filled. So, a lot of spaces is formed betweenthe crystal tubes 61 used for protecting the metallic photocatalystcoating supporters 67 and the ultraviolet ray lamp 62, so that thephotocatalyst coating supporters 67 may move based on the flow of waterand may collide with each other for thereby damaging the crystal tube61. However, in the present invention, the photocatalyst coatingsupporters 67 are stably fixed with each other by means of the tensionalforce of the coil spring 67 a and do not move by means of the flow ofwater, so that it is possible to prevent the crystal tubes 61 from beingbroken.

In a waste water treatment system and method using a high pressureadvanced oxidation process with unreacted ozone reusing according to thepresent invention, the ultraviolet ray discharged from the ultravioletlamp 62 may be classified into a vacuum UV which creates ozone inreaction with oxygen based on wavelengths, a UV-C 200˜280 nm which hassanitization and decomposes ozone, and a UV-A,B 280˜400 nm which isgenerally used for a photocatalyst reaction. When the UV-C 200˜280 nm ispassed through the dissolved ozone, the ozone absorbs the ultravioletray and photo-decomposes the same for thereby creating H₂O₂ as anintermediate substance. The pollutant is decomposed by means of an OHradical which is created as H₂O₂ is decomposed.

In a waste water treatment system and method using a high pressureadvanced oxidation process with unreacted ozone reusing according to thepresent invention, the ultraviolet ray used in reaction for creating OHradical by decomposing the ozone in the advanced oxidation process inthe photocatalyst reaction which uses ultraviolet ray may use a lowpressure or high pressure Ag ultraviolet ray lamp which emits 254 nmwavelengths which is able to decompose ozone, and an intermediatepressure lamp which emits ultraviolet ray of various wavelengths fromUV-C to UV-A. Here, the 254 nm ultraviolet ray having a short wavelengthhas just 2˜3 nm of underwater penetration power. So, only ozone near thecrystal tube 61 having the ultraviolet ray lamp 62 reacts. The holes areformed near the crystal tube having the ultraviolet ray lamp in thephoto-oxidation reaction apparatus of the Korean patent registrationnumber 0541573 so that ozone foams can pass, so that the ozone isdecomposed by means of ultraviolet ray while ozone passes through nearthe ultraviolet ray lamp, and the creation amount of OH radicalincreases for thereby enhancing the decomposition reaction efficiency ofthe pollutant.

In a waste water treatment system and method using a high pressureadvanced oxidation process with unreacted ozone reusing according to thepresent invention, the ultraviolet ray lamp 62 used in the high pressureadvanced oxidation process formed of the high pressure photo-oxidationreaction apparatus 60 filled with the photocatalyst coating supporter 67uses an intermediate pressure ultraviolet ray lamp which emits variouswavelengths lights from ultraviolet ray to visible ray, the OH radicalis created based on the photo-oxidation decomposition reaction by meansof the UV-C 254 nm wavelength ultraviolet ray having a weak transitivitynear the crystal tube 61. The photocatalyst coating supporter 67positioned relatively far from the crystal tube 61 may be used fordecomposing the pollutant by creating OH radical as the ozone isdecomposed based on the photo-oxidation reaction by means of the UV-Aand B 280˜400 nm which may reach far since it has a relatively betterpenetration power with its longer wavelength as compared to the UV-C.The reaction that the OH radical created based on the pollutantoxidation reaction by means of the increased dissolved ozone, thedecomposition reaction of the ozone by means of the ultraviolet ray, andthe ozone decomposition reaction by means of the ultraviolet ray and thephotocatalyst decomposes the pollutants and the reaction that the OHradical created as the ultraviolet ray and the photocatalyst decomposewater decomposes the pollutants are concurrently performed, so that itis possible to significantly increase the decomposition speed of thepollutants. In particular, it is possible to maximize the undecomposablesubstances.

In the above, the waste water treatment system and method using a highpressure advanced oxidation process with unreacted ozone reusingaccording to the present invention were described just as anillustrative purpose for implementing the present invention. It is notlimited to the technical scope of the present invention. The protectionscope of the present invention may be defined by means of the claims.Those who skilled in the art may modify or change without escaping fromthe gist of the present invention, and such medication and change may bealso included in the scope of the present invention.

Advantageous Effects

In the waste water treatment system and method using a high pressureadvanced oxidation process with unreacted ozone reusing according to thepresent invention, the ozone being present in the foams due to a lowunderwater dissolubility in a conventional normal pressure advancedoxidation process has a low contact efficiency with the pollutant, sothat there is a lot of unreacted ozone. However, in the presentinvention, the advanced oxidation process, which has been conducted at anormal pressure in the conventional art, is changed to a high pressureenvironment for thereby dissolving a lot of ozone, so that it ispossible to enhance a contact efficiency of the ozone with thepollutant. As the creation of the OH radical having a strong oxidationpower by means of the photo-oxidation reaction of the ultraviolet rayand ozone increases, the pollutant decomposition speed increases. Inaddition, the unreacted ozone, which was directly discharged into theair in the conventional art, is treated along with the floatation andremoval method of the floated substances in the waste water based on thedissolved ozone/air flotation separation method in the pretreatmentflotation tub and the gas-liquid separation flotation tub. Theefficiency of the use of the ozone increases by reusing the unreactedozone which allows the pollutant to be removed, so that it is possibleto decrease the capacity of the advanced oxidation process wastetreatment apparatus and the capacity of the expensive ozone generator,whereby the installation cost and the operation cost can besignificantly decreased, and the waste water treatment apparatus of theadvanced oxidation process can be made in a compact size.

In addition, in a waste water treatment system and method using a highpressure advanced oxidation process with unreacted ozone reusingaccording to the present invention, the ozone inputted into the highpressure advanced oxidation process waste water treatment system istreated via four reaction steps for thereby increasing an efficiency ofthe decomposition reaction of the ozone, so that it is possible tominimize the amount of unreacted ozone, and it is possible to perform adesired reaction only with the ozone needed for the pollutantdecomposition reaction. The capacity of the expensive ozone generatorcan be reduced as compared to the conventional advanced oxidationprocess which uses a large capacity ozone generator in which almostozone is discharged into the air. In addition, it is possible todecrease the load of the off-gas ozone removing apparatus for removingthe off-gas ozone which is discharged into the air.

DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view illustrating a waste water treatment systemused in a waste water treatment method using a high pressure advancedoxidation process with unreacted ozone reusing according to the presentinvention.

FIG. 2 is a view illustrating a high pressure photo-oxidation reactionapparatus used in a waste water treatment method using a high pressureadvanced oxidation process with unreacted ozone reusing according to thepresent invention.

FIG. 3 is a view illustrating a coil spring type supporter coated with aphotocatalyst, a photocatalyst coated on a coil spring surface and awire surface according to the present invention.

FIG. 4 is a comparison graph of a salt-pickled cabbage salt water CODdecomposition ratio based on a high pressure advanced oxidation reactionand a normal pressure advanced oxidation reaction according to thepresent invention.

FIG. 5 is a comparison graph of a salt-pickled cabbage salt waterturbidity removal ratio based on a high pressure advanced oxidationreaction and a normal pressure advanced oxidation reaction according tothe present invention.

BEST MODE

In the present invention, there is provided a waste water treatmentsystem using a high pressure advanced oxidation process by using aunreacted ozone which comprises a high pressure photo-oxidation reactionapparatus which includes a housing having an inlet for receiving anozone-dissolved source water and a discharge port for discharging theinputted source water, an ultraviolet lamp which is installed in theinterior of the housing for irradiating ultraviolet ray to the sourcewater inputted into the interior of the housing, and a photocatalystcoated supporter which is filled into the interior of the housing; apressurizing pump which pumps the source water into the inlet of thehousing of the high pressure photo-oxidation reaction apparatus; anozone generator of which ozone supply line is connected with a sourcewater line connected with a suction port of the photo-oxidationpressurizing pump for thereby generating ozone, so that the generatedozone is spread into the source water which is inputted via the suctionport of the photo-oxidation pressurizing pump; and a gas-liquidseparation flotation tub which has a scum removing port for dischargingfloated substances which are floated in an absorbed state to a microfoam ozone generated from the ozone dissolved in the treatment waterinputted into the interior of the reaction tub, with an inlet port ofthe same being provided at a lower side of the reaction tub so that thetreatment water discharged from the discharge port of the housing of thehigh pressure photo-oxidation reaction apparatus is inputted into theinterior of the reaction tub which is open so that a normal pressure isformed in the interior of the same, with a discharge port being providedat the reaction tub for ensuring that the treatment water inputted intothe interior of the reaction tub is discharged.

Mode for Invention

The waste water treatment system and method using a high pressureadvanced oxidation process with unreacted ozone reusing according to thepresent invention will be described in more detail with reference to theaccompanying drawings.

FIG. 1 is a schematic view illustrating a waste water treatment systemused in a waste water treatment method using a high pressure advancedoxidation process with unreacted ozone reusing according to the presentinvention. FIG. 2 is a view illustrating a high pressure photo-oxidationreaction apparatus used in a waste water treatment method using a highpressure advanced oxidation process with unreacted ozone reusingaccording to the present invention. FIG. 3 is a view illustrating a coilspring type supporter coated with a photocatalyst, a photocatalystcoated on a coil spring surface and a wire surface according to thepresent invention. FIG. 4 is a comparison graph of a salt-pickledcabbage salt water COD decomposition ratio based on a high pressureadvanced oxidation reaction and a normal pressure advanced oxidationreaction according to the present invention. FIG. 5 is a comparisongraph of a salt-pickled cabbage salt water turbidity removal ratio basedon a high pressure advanced oxidation reaction and a normal pressureadvanced oxidation reaction according to the present invention.

As shown in the drawings, a waste water treatment system 100 using ahigh pressure oxidation process having a unreacted ozone reuse processaccording to an embodiment of the present invention comprises a wastewater storing tub 10 for storing waste water, and a pretreatmentflotation tub 30 which removes floating substances and pollutant inwaste water with the unreacted ozone. Here, the pretreatment flotationtub 30 includes first and second pretreatment floatation tubs 30 a and30 b. The waste water treated in the pretreatment floatation tub 30 istransferred to the high pressure photo-oxidation reaction apparatus 60which decomposes the pollutants based on the photo-oxidation reaction bypressurizing along with the ozone supplied from the ozone generator 70using the pressurizing pump 65. There is provided a feedback line 69which feeds back part of a high pressure reaction substance of the highpressure photo-oxidation reaction apparatus 60 to the secondpretreatment flotation tub 32. A treatment water circulation line 63 isconnected at an intermediate portion of the feedback line 69 with acirculation pump 63 a for circulating a high pressure reaction substanceto the high pressure photo-oxidation apparatus 60, a flow meter 63 b anda flow rate adjusting valve 63 being installed at the treatment watercirculation line 63. In addition, there is provided a gas-liquidseparation flotation tub 40 which removes the pressure of the highpressure reaction substance of the high pressure photo-oxidationreaction apparatus 60 and removes the remaining pollutants in thetreatment water based on the dissolved ozone/air flotation separationmethod. The unreacted ozone collected at the upper side of thegas-liquid separation flotation tub 40 is transferred to thepretreatment flotation tub pressurizing pump 35 along with the wastewater and is inputted into the first pretreatment flotation tub 31 forthereby finally removing the unreacted ozone based on the dissolvedozone/air flotation separation method. The unreacted ozone is removedbelow the environment standard value by transferring the same to theoff-gas ozone removing apparatus 50 via the flotation tub discharge port31 c of the first pretreatment flotation tub 31 before discharging thesame into the air.

The advanced oxidation process waste water treatment apparatus 100 usingthe high pressure photo-oxidation decomposition reaction apparatus 60according to the present invention is implemented via a first stepunreacted ozone reuse process of the second pretreatment flotation tub32 and the gas-liquid separation flotation tub 40, in which the wastewater first treated with the ozone is pressurized with a high pressureusing the pressurizing pump 65 in the process which uses a unreactedozone and is decomposed by means of the photo-oxidation reaction in thehigh pressure photo-oxidation decomposition apparatus 60, and thefloating substances among the waste water are floated based on thedissolved ozone/air flotation separation method with respect to theunreacted ozone contained in the high pressure reaction substance andare reacted with the pollutant and are removed, and a second stepunreacted ozone reuse process of the first pretreatment flotation tub 31in which the waste water of the waste water storing tub 10 and theunreacted ozone collected at the upper sides of the second pretreatmentflotation tub 32 and the gas-liquid separation flotation tub 40 arepressurized along with the flotation tub pressurizing pump 35 forthereby removing the floating substances and pollutant contained in thewaste water based on the dissolved ozone/air flotation separationmethod. In the process for reusing the first and second step unreactedozone, there are provided a scum removing apparatus (not shown) whichremoves the foams at the upper sides of the pretreatment flotation tubs31 and 32 and the gas-liquid separation flotation tub 40, and scumtreatment tubs 31 d, 32 d and 40 d which store and discharge the removedscum.

The high pressure photo-oxidation reaction apparatus 60 pressurizes theozone supplied from the ozone generator 70 and the waste water twicetreated by the first and second pretreatment flotation tubs 30 a and 30b with a certain pressure so that the amount of the foam ozone inputtedinto the photo-oxidation pressurizing pump 65 is minimized. The pressureand flow rate of the high pressure photo-oxidation reaction apparatus 60are preferably adjusted by means of a method for adjusting therevolution of the pressurizing pump 65 at the flow rate set by thepressure meter 64 b, the flow meter 64 a and the flow rate adjustingvalve 64 c. In a feedback system, part of all of the treatment water isfed back to the second pretreatment flotation tub 32 via the feedbackline 69 connected with the discharge port 60 b of the high pressurephoto-oxidation reaction apparatus 60 in consideration with the loadadjusting of the high pressure photo-oxidation reaction apparatus 60 andthe operation efficiency of the pretreatment floatation tub 30. Inaddition, the lower inlet 60 a of the photo-oxidation reaction apparatus60 is connected with the treatment water feedback line 69 connected withthe discharge port 60 b of the high pressure photo-oxidation reactionapparatus 60 via the circulation line 63 a having the photo-oxidationcirculation pump 63, the flow meter 63 b, and the flow rate adjustingvalve 63 c. so, it is possible to perform the high pressurephoto-oxidation reaction while adjusting the photo-oxidation reactionlevel and the amount of the unreacted ozone by circulating part or allof the high pressure reaction substance.

The high pressure photo-oxidation reaction apparatus 60, which performsa photo-oxidation decomposition reaction with a high pressure, is formedof a tube shaped housing 66 having a rectangular or circular crosssection. Here, the housing 66 is made of stainless steel or titanium andcomprises a lower inlet 60 a connected with the photo-oxidationpressurizing pump 65, an upper discharge port 60 b which is connectedwith the treatment water feedback line 69 and the gas-liquid separationflotation tub 40, and a crystal tube fixing unit 68 which accommodatesthe ultraviolet lamp 62 at the upper side of the housing 66 and fixesthe U-shaped crystal tube 61. In the housing 61, at least one crystaltube 61 is installed in the longitudinal direction of the housing 61.The photocatalyst coated supporter 67 may be filled in the inner spaceof the crystal tube 61 and the housing 66.

The reaction with respect to the ozone in the high pressurephoto-oxidation reaction apparatus 60 may be classified into four steps.Namely, 1) the ozone is directly reacted with the pollutant, 2) theozone absorbs the light of wavelength of 254 nm and creates OH radicaland reacts with the pollutant, 3) the ozone is decomposed by means ofthe ultraviolet ray and the photocatalyst reaction and creates OHradical and reacts with the pollutant, and 4) as the ultraviolet rayreacts with the photocatalyst, and water is decomposed, and OH radicalis created and reacted with pollutant. The above four steps may beconcurrently performed. The ultraviolet ray used in the second, thirdand fourth reactions may use low pressure and high pressure Ag lampswhich selectively irradiate wavelengths of 254 nm. In the third andfourth photocatalyst reactions, an intermediate pressure Ag lamp havinga wider width of ultraviolet ray emission is preferred since the 254 nmultraviolet ray of a shorter wavelength has a penetration power of a fewnm. So as to increase the penetration power, a high output lamp isdisadvantageously needed. Since only the portions near the crystal tube61, which protects the ultraviolet lamp 62, can be used for reaction,more ultraviolet lamps are needed and the arrangement of the ultravioletlamps should be disadvantageously intensified.

The ultraviolet lamp 62 may be formed of a low pressure or high pressureAg ultraviolet ray lamp which irradiates a UV-C 254 wavelength or anintermediate pressure ultraviolet ray lamp which irradiates ultravioletray of UV-A, B and C. A stabilizer system is installed for flashing theultraviolet ray lamp 62 with a single output and is able to adjust theoutput of the ultraviolet ray lamp 62 with 5˜12%.

Among the pollutants, a certain pollutant may be sanitized only with areaction by ozone under a condition that does not need ultraviolet rayand photocatalyst. In the present invention, the source waterpressurized by the photo-oxidation pressurizing pump 65 is not directlyinputted into the high pressure photo-oxidation reaction apparatus 60,but is passed via the high pressure ozone reaction apparatus 90 and isinputted into the high pressure photo-oxidation reaction apparatus 60.Since the source, water which was previously ozone-reacted before thephoto-oxidation reaction, is processed via the photo-oxidation reactionby the high pressure photo-oxidation reaction apparatus 60, so that itis possible to decrease any load of the ozone reaction in the highpressure photo-oxidation reaction apparatus 60. As shown in thedrawings, an opening and closing valve 60 b provided at the pipeextended to the lower inlet 60 a of the high pressure photo-oxidationreaction apparatus 60 is closed, and the opening and closing valve 91 aprovided at the pipe 91 extended from the photo-oxidation pressurizingpump 65 to the high pressure ozone reaction apparatus 90 is opened, thesource water pressurized by means of the photo-oxidation pressurizingpump 65 is inputted into the high pressure ozone reaction apparatus 90and is inputted into the high pressure photo-oxidation reactionapparatus 60 via the pipe 92 connected with the lower inlet 60 a of thehigh pressure photo-oxidation reaction apparatus 60. The pipe 92connected with the lower inlet 60 a of the high pressure photo-oxidationreaction apparatus is closed by means of the opening and closing valve92 a of the pipe 92.

The lower inlet 60 a of the photo-oxidation reaction apparatus 60 isconnected with the treatment water feedback line 69, which transfers ahigh pressure substance to the second pretreatment tub via the upperdischarge port 60 b of the high pressure photo-oxidation reactionapparatus 60, via the circulation line 63 which has the flow meter 63 b,the flow rate adjusting valve 69 c, and the circulation pump 63 a. Theefficiency of the photo-oxidation decomposition reaction of the wastewater can be adjusted based on the method for circulating part or all ofthe treatment water fed back via the treatment water feedback line 69 tothe high pressure photo-oxidation reaction apparatus.

The lower discharge port 39 b of the second pretreatment flotation tub32 is connected with the photo-oxidation pressurizing pump 65 via thephoto-oxidation waste water supply tube 39 having the flow rateadjusting valve 39 b, and the photo-oxidation waste water supply tube 39is connected with the ozone generator 70 via the ozone supply line 71having a check valve 71 c, a flow meter 71 b, and a flow rate adjustingvalve 71 a. Here, the photo-oxidation pressurizing pump 65 pressurizeswaste water and ozone at above three atmosphere and supplies the ozonedissolved waste water to the high pressure photo-oxidation reactionapparatus 60. In the high pressure photo-oxidation reaction apparatus60, the housing 66 having a circular or rectangular cross section has aninlet 60 a and an output 69 b. A crystal tube fixing unit 68 is providedat an upper side of the housing 66 for fixing a U-shaped crystal tube 61having one closed end for thereby accommodating the ultraviolet ray lamp62. The crystal tube fixing unit 68 fixes an open outer diameter portionof the U-shaped crystal tube 61 for sealing with respect to the highpressure photo-oxidation reaction apparatus 60. Namely, it is sealedusing a fluorine resin or silicon O-ring or gasket which is not agedwith respect to irradiation of the ultraviolet ray with respect to aninner wall of the crystal tube fixing unit 68. The crystal tube 61 isinstalled at the center of the high pressure photo-oxidation reactionapparatus in a longitudinal direction of the same. Here, the crystaltube 61 preferably has a thickness of over 2 mm so as to endure a highpressure photo-oxidation reaction pressure. When at least one crystaltube 61 is installed, the crystal tubes should be installed at regularintervals in the high pressure photo-oxidation reaction apparatus 60, sothat uniform irradiation amount of ultraviolet ray is outputted. Thephotocatalyst coating supporter 67 is filled between the outer wall ofthe crystal tube 61 and the high pressure photo-oxidation reactionapparatus 60.

In the present invention, there is provided a treatment water feedbackline 69 for feeding back a high pressure reaction substance of thedischarge port 60 b of the high pressure photo-oxidation reactionapparatus 60 to the lower input port 32 c of the second pretreatmentfloatation tub 32 so as to adjust a pollutant substance load adjustinglevel of the high pressure photo-oxidation reaction apparatus 60 and areaction time of the waste water of the high pressure photo-oxidationreaction apparatus 60. In addition, a treatment water circulation line63 is installed for circulating a high pressure reaction substance fromthe intermediate portion of the treatment water feedback line 69 to thelower inlet port 60 a of the high pressure photo-oxidation reactionapparatus 60. Flow meters 63 b and 69 a and flow rate adjusting valves63 c and 69 b are installed at the treatment water feedback line 69 andthe circulation line 63. A high pressure reaction substance is inputtedinto the second pretreatment floatation tub 32 by its pressure, and thecirculation to the lower inlet port 60 a of the high pressurephoto-oxidation reaction apparatus 60 is performed by means of thecirculation pump 63 a.

In the present invention, the high pressure reaction substance reactedin the first high pressure photo-oxidation reaction apparatus 60 istransferred by means of the pretreatment floatation and gas-liquidseparation floatation tub, and the floating substance and pollutant areremoved by means of the dissolved ozone/air floatation method, and thepollutant contained in the waste water inputted into the high pressurephoto-oxidation reaction apparatus 60 is previously removed. Since it ispossible to adjust the pollutant decomposition efficiency by adjustingthe staying time of the waste water of the photo-oxidation decompositionapparatus 60 as the high pressure reaction substance is circulatedtoward the photo-oxidation decomposition apparatus 60. So, it isadvantageously operate the high pressure advanced oxidation processwaste water treatment apparatus 100 using the high pressurephoto-oxidation reaction apparatus 60 with respect to the changes inpollutant concentration and treatment amount of the waste water.

In the present invention, in the step for removing a unreacted ozone inthe gas-liquid separation flotation tub 40, a high pressure reactionsubstance discharged via the discharge port 60 b of the high pressurephoto-oxidation reaction apparatus 60 is discharged to the lower inletport 40 a of the gas-liquid separation flotation tub 40. Micro sizeunreacted ozone foams created as the solubility sharply decreases due tothe pressure difference are floated toward the upper side of thetreatment water in the gas-liquid separation floatation tub 40 and reactwith the remaining pollutants, so that the pollutants and unreactedozone are removed based on the dissolved ozone/air flotation process.The unreacted ozone remaining after the dissolved ozone/air flotationprocess are collected at the upper side of the gas-liquid separationflotation tub 40 and are transferred to the flotation tub pressurizingpump 35 and are processed via the dissolved ozone/air flotation processin the first pretreatment flotation tub 31. So, the unreacted ozone isminimized, and is transferred to the off-gas ozone removing apparatusand is discharged into the air at a proper concentration in compliancewith the environment standard.

A small amount of ozone may be present in the discharged off-gas afterthe pretreatment process. Since the ozone of the stratosphere absorbsharmful ultraviolet ray, the ozone near the ground may cause a breathingrelated disease and allows a photo chemical smog to increase based on areaction with the VOC and Nox. According to the OSHA (OccupationalSafety and Health Administration), the permissible exposing degree for 8hours is about 0.1 ppm. The ozone in a range of 0.1˜1 ppm may causeheadache, throat dryness and may affect mucous membrane.

In the off-gas ozone removing apparatus 50 for removing a small amountof ozone contained in the discharged off-gas, one amongphotocatalyst-coated active charcoal, metallic net, metallic coilspring, etc. is filled near the ultraviolet lamp installed at thestainless steel tube through which the unreacted ozone passes, and theultraviolet ray is irradiated onto the photocatalyst, so that theunreacted ozone is decomposed by means of the photo-oxidationdecomposition reaction. The hollow cylindrical crystal or stainlesssteel tube having a diameter of 5˜20 mm, a length of 5˜30 mm, and athickness of 1˜3 mm is filled into the interior of the tube of thecrystal or stainless steel through which the unreacted ozone passes. Themesh processed with a stainless steel having a diameter of below 2 mm isstacked and filled. They are heat-decomposed at a temperature of about200° C. by means of a heating wire of which temperature can becontrolled.

In the present invention, the floatation tub pressurizing pump 35 andthe high pressure photo-oxidation pressurizing pump 65 used for mixingand dissolving unreacted ozone in the waste water may use a DAF pump ordoes not use a method for inputting ozone by pressurizing the compressedwaste water using a compressor. Namely, it is preferably pressurizedalong with the waste water using a common pressurizing pump such as ahorizontal or multi-step pump, a gear pump, a piston pump, a loaderpump, a procon pump, etc. The dissolving degree of ozone can becontrolled by means of the amount of inputted ozone and the pressure. Itis possible to easily check the change of the amount of foams in thewaste water via a vie window of the surface area based flow meter as thesolubility of the ozone increases when the reaction pressure isincreased.

In the present invention, in the ozone inputted into the high pressurephoto-oxidation reaction apparatus 60, as the solubility of the ozoneincreases, the amount of the ozone of the foam shape decreases, so thata needed ultraviolet ray irradiation is smoothly performed. So, thephotocatalyst and photo-oxidation decomposition reaction of ozone areactively performed, so that the amount of the creation of the OH radicalincreases. The photocatalyst coated supporter 67 filled in the innerspace of the photo-oxidation reaction apparatus 60 is a coil spring type67 a of the supporter 67. The ultraviolet ray can be easily irradiatedthrough the spaces between the pitches and the water containingpollutant can easily flow between the same, so that the pressure loss isminimized, and when the supporter 67 of the coil spring 67 a is filledin the high pressure photo-oxidation reaction apparatus 60, and thesupporter 67 of the coil spring 67 a is compressed and filled, they canbe stable filled by means of the tensional force of the spring of thefilled photocatalyst coated supporter 67, so that it is possible toprevent the crystal tube 61 from being damaged by the flow of the filledsupporters by means of the flow resistance of the water. So, the coilspring type supporters having elastic forces are preferred.

In the present invention, the supporter of the coil spring 67 a is madeof a wire having a diameter of 0.1˜5 mm, and the diameter of the coilspring 67 a is 5˜7 mm, and the pitch of the same is smaller than thediameter of the wire 67 b, so that it is preferred to prevent the coilspring 67 a from being inserted into each other in the course of thefilling into the high pressure photo-oxidation reaction apparatus 60 andto prevent the filling rate from being low.

Namely, when the stainless steel or titanium wire having a diameter of0.1˜5 mm is made in a coil spring shape 67 a of the photocatalyst coatedsupporter 67, the coil spring 67 a is made in a hourglass shape. Thepitch of the spring is smaller than the diameter of the wire 67 b. Thepitch of the beginning and ending portions of the spring are near theneighboring pitch, so that the supporters of the coil springs 67 a arenot overlapped in the course of filling. The wire surfaces 67 are madetough by colliding sand or diamond sand to the wire 67 b along with highpressure air in the sanding process. The titanium alkoxide may be coatedand heat-treated under a temperature of 800° C.

In the high pressure advanced oxidation process waste water treatmentsystem 100 which reuses unreacted ozone according to the presentinvention, the pollutant contained in waste water is decomposed by meansof a lot of dissolved ozone, and the dissolved ozone reacts with thepollutant based on the OH radical having a strong oxidation powercreated by means of the photo-oxidation reaction of the ultraviolet rayand the photocatalyst 67 d and is decomposed, so that a high reactionefficiency can be obtained.

In the present invention, the ultraviolet lamps 62 may be installed inmultiple numbers depending on the treatment capacity of the highpressure photo-oxidation reaction apparatus 60. The ultraviolet lamps 62are protected in the crystal tube 61 so as to avoid a direct contactwith the waste water and are arranged longitudinally in the up and downdirections in the interior of the high pressure photo-oxidation reactionapparatus 60. Here, the ultraviolet ray lamp 62 is electricallyconnected with the power supply panel unit 80 which supplies power, andthe stabilizer system, which drives the ultraviolet lamp 62, is providedwith a certain unit for viewing the operation state from the outside. Itis preferred to adjust the output of the ultraviolet lamp up to 5˜120%variably based on the treatment level of the waste water. The stabilizersystem may be adapted and turned on and off so that the ultraviolet lamp62 may be turned on with a single output or the output of the same canbe variably adjusted within 5˜120%. Here, the ultraviolet lamp 62 is alow or high pressure Ag ultraviolet lamp which emits UV-C 254 nmwavelength or an intermediate pressure ultraviolet lamp which emitsUV-A, B, C wavelengths.

At the rear ends of the first pretreatment flotation tub 31 and the highpressure photo-oxidation reaction apparatus 60, pressuresensor-installed digital pressure meters 36 a and 64 b for transmittingand receiving analog or digital signals, floatation pressurizing pump 35and photo-oxidation pressurizing pump 65 of which revolutions can beadjusted, and flow rate adjusting valves 34 c and 64 c which operatebased on pneumatic or electric motor are installed, respectively. Whenthe pressures of the floatation tub pressurizing pump 35 and the highpressure photo-oxidation reaction apparatus 60, which have directinfluences with the solubility of the gaseous ozone and with thefloatation capacity of the dissolved ozone/air flotation separationmethod, are adjusted, it is needed to constantly fix the dischargeamount, and the revolutions of the floatation pressurizing pump 35 andthe photo-oxidation pressurizing pump 65 are synchronized with the setpressure. In addition, it is preferred to directly check the dissolvingdegree of the ozone by installing the surface area type flow meters 34 aand 64 a for thereby checking the amount of gas contained in the liquid.

The photocatalyst coated supporter 67 filled between the crystal tube 61having the ultraviolet ray lamp 62 in the interior of the high pressurephoto-oxidation reaction apparatus 60 and the photo-oxidation reactionapparatus housing 66 is hollow and made is an egg shaped coil spring 67a by which the ultraviolet ray can irradiate via the space between thespring pitches, and the reaction substance flows without pressure loss.When they are filled in the interior of the high pressurephoto-oxidation reaction apparatus 60, they are compressed using thetensional force of the coil spring 67 a and are filled, so that thephotocatalyst coated supporters 67 are stably fixed without movements bymeans of the fluid. So, it is possible to prevent the damage of thecrystal tube 61 by means of the collision between the photocatalystcoated supporters 67, and to prevent any loss of the coatedphotocatalyst 67 d. The high pressure photo-oxidation reaction apparatus60 filled with the photocatalyst coated supporter 67 in a shape of thecoil spring 67 a has a large valid reaction surface area for irradiationof the ultraviolet ray as the photocatalyst supporters are arranged in a3D structure.

In the case that the photocatalyst of the Korean patent number 541573 iscoated on a porous plate, the size of the hole formed at the plate issmaller, the surface area may be increased, and then the activation maybe enhanced. However, the pressure loss increases, so that it isimpossible to increase the treatment capacity. On the contrary, thenumber of the holes increases or the size of the same is large, thepressure loss may be small, but the reaction surface area is small, sothat the activations can be less.

In the present invention, the photocatalyst coated supporters 67 may befilled into the interior of the high pressure photo-oxidation reactionapparatus in a 3D structure, so that the pressure loss is minimized, andthe filling intensity may be enhanced. So, as the photocatalyst coatedsupporters 67 are filled, the surface area increased, and thephotocatalyst precursor substances are coated on the outer surface 67 ctough-processed by means of the sanding work or chemical such as acidwith respect to the surface of the coil spring 67 a and areheat-treated, so that it is possible to enhance the attaching powerbetween the tough processed outer surfaces 67 c and the photocatalyst 67d. Here, with the increased surface area of the tough outer surface 67c, the frequency of the photo-oxidation reaction with the pollutant inthe dissolved ozone and the waste water can be enhanced, so that thereaction frequency is increased. So, the efficiency of thephoto-oxidation decomposition reaction is enhanced, and the waste waterdecomposition reaction efficiency can be increased.

The floatation tub pressurizing pump 35, which is used for pressurizingalong with the waste water for reusing the unreacted ozone collected bythe first pretreatment floatation tub 32 and the gas-liquid separationfloatation tub 40 based on the dissolved ozone/air floatation separationmethod, and the photo-oxidation pressurizing pump 65 which pressurizesthe ozone supplied from the ozone generator 70 and the waste waterprocessed in the second pretreatment floatation tub 32 may be formed ofa horizontal or upright type multistage pump which is able to suck andpressurize the unreacted ozone and the waste water or mat be formed ofone among the lobe pump, gear pump, procon pump. In addition, thepressures of the floatation tub pressurizing pump 35 and thephoto-oxidation pressurizing pump 65 can be adjusted by adjusting therevolution of the pressurizing pump with set pressures in a state theflow rate is fixed.

In the present invention, there is provided a waste water treatmentmethod using a high pressure advanced oxidation process by using aunreacted ozone which comprises a pressurizing step in which a wastewater to be treated is pressurized with a high pressure by means of aphoto-oxidation pressurizing pump along with an ozone generated by anozone generator; a photo-oxidation decomposition step in which apollutant of the pressurized waste water is decomposed based on aphoto-oxidation reaction using a high pressure photo-oxidation reactionapparatus; a unreacted ozone first reuse step in which a high pressurereaction substance of the high pressure photo-oxidation reactionapparatus is inputted into a treatment water of the first treatmentwaste water and gas-liquid separation flotation tub of the secondpretreatment floatation tub, and the floating substance and thepollutant are removed based on a DOF (Dissolved Ozone/Air flotation)method; a unreacted ozone second reuse step in which a gas containing aunreacted ozone collected at the upper sides of the second pretreatmentfloatation tub and the gas-liquid separation floatation tub ispressurized with a high pressure along with the waste water suppliedfrom the waste water storing tub using the floatation pressurizing pump,and the waste water of the first pretreatment floatation tub inputtedfrom the waste water strong tub is treated based on the dissolvedozone/air flotation method for thereby removing the floating substanceand the pollutant; and an ozone decomposition step which decomposes aremaining unreacted ozone discharged from the first pretreatmentflotation tub by using an off-gas ozone removing apparatus.

The unreacted ozone first and second reuse steps which reuse a unreactedozone are implemented by means of the first and second pretreatmentfloatation tubs and the gas-liquid separation floatation tub so that theunreacted ozone is reused for removing the floating substance and thepollutants in the waste water based on the dissolved ozone/air flotationseparation method using the unreacted ozone and air mixed gas; and thedissolved ozone/air floatation separation method of the secondpretreatment floatation tub and the gas-liquid separation floatation tubin the unreacted ozone first reuse step are directed to removing thepollutants based on the dissolved ozone/air floatation separation methodby inputting an ozone pressurized by the photo-oxidation pressurizingpump and a high pressure reaction substance discharged via the dischargeport after the reaction in the high pressure photo-oxidation reactionapparatus into the second pretreatment floatation tub having a wastewater and into the gas-liquid separation floatation tub having atreatment water; and in the unreacted ozone second reuse process, theremaining unreacted ozone discharged from the second pretreatmentfloatation tub and the gas-liquid separation floatation tub arecollected, and are pressurized with more than three atmosphere alongwith the waste water supplied from the waste water storing tub by usingthe floatation tub pressurizing pump, and the floating substance and thepollutants are removed from the waste water of the first pretreatmentfloatation tub based on the dissolved ozone/air floatation separationmethod; and the first and second pretreatment floatation tubs and thegas-liquid separation floatation tub used in the unreacted ozone firstand second reuse processes are provided with the scum discharge portsfor separating the scum from the water surface and discharging the same.

The floatation tub pressurizing pump used for pressurizing the unreactedozone along with the waste water for reusing the unreacted ozonecollected by the first pretreatment floatation tub and the gas-liquidseparation floatation tub based on the dissolved ozone/air floatationseparation method and the photo-oxidation pressurizing pump forpressurizing the ozone from the ozone generator and the waste watertreated in the second pretreatment floatation tub are one among ahorizontal or upright multiple stage pump, a lobe pump, a gear pump anda procon pump for sucking and pressurizing the unreacted ozone or ozonealong with the waste water; and the pressures of the floatation tubpressurizing pump and the photo-oxidation pressurizing pump are adjustedby adjusting the revolution of the pressurizing pump with a set pressurein a state that the flow rate is fixed.

In the following, the turbidity of salt water and COD removing effectsare compared when the cabbage pickling salt water in the Kimchi factoryis treated using the high pressure photo-oxidation decompositionapparatus 60 of the present invention based on the high pressureadvanced oxidation process and when it is treated based on the normalpressure advanced oxidation process.

(Experiment)

20 liter of salt water from which foreign substances are removed using afilter is filled in a storing receptacle. 100 ml/min of the ozonecontained gas generated by the ozone generator (5 g/hour) and 5liter/min are sucked using the procon pump and are pressurized up tofive atmosphere and are transferred to the photo-oxidation decompositionapparatus provided with the 75 W ultraviolet lamp and the photocatalystfor thereby performing a photo-oxidation decomposition reaction. Thedischarged high pressure reaction substance is 100% circulated down inthe salt storing tub, and the unreacted ozone is reused based on thedissolved ozone/air flotation separation method, and the floated scum isdischarged via the air outlet of the upper side of the storing tub alongwith the air and is removed. In case of the normal pressure advancedoxidation reaction, only the pressure is changed to a normal pressure,and the other conditions are same. The salt water is collected by eachtime, and the COD and turbidity are checked, and a result is obtained asshown in FIGS. 4 and 5. As a result obtained after purifying the saltwaste water having the initial COD of 410 ppm, and the turbidity of 21,a significant difference was obtained as shown in FIG. 4 between theadvanced oxidation process using a high pressure photo-oxidationreaction and a conventional normal pressure advanced oxidation process.

INDUSTRIAL APPLICABILITY

In the waste water treatment system and method using a high pressureadvanced oxidation process with unreacted ozone reusing according to thepresent invention, the efficiency of use is enhanced with a unreactedozone reuse process, and the capacities of the advanced oxidationprocess waste water treatment apparatus and expensive ozone generatordecrease, so that it is possible to significantly decrease theinstallation and operation costs. The advanced oxidation process wastewater treatment apparatus may be made in a compact size. With the aboveadvantages, the present invention may be well adapted to a region whereit is not easy to obtain a needed area for a waste water treatmentfacility such as a city building, factory, apartment, public facility,etc. In addition, it can be well adapted to a heavy water treatmentsystem which cannot use a conventional biological treatment method owingto smell and outer look problems. Further more, the present invention isable to effectively treat in a water purification factory, a golf fieldand a waste extraction water area in a burying area.

Sequence List Text

water, treatment, photocatalyst, photo-oxidation, high pressure

The invention claimed is:
 1. A water treatment method, comprising: apressurizing step in which a waste water to be treated is pressurizedwith a high pressure by a photo-oxidation pressurizing pump along withan ozone generated by an ozone generator; a photo-oxidationdecomposition reaction step in which a pollutant of the pressurizedwaste water is decomposed based on a photo-oxidation reaction using ahigh pressure photo-oxidation decomposition reaction apparatus; anunreacted ozone first reuse step in which a high pressure reactioneffluent from the high pressure photo-oxidation reaction apparatus isinputted into both a downstream gas-liquid separation flotation tub andan upstream second pretreatment floatation tub, and the floatingsubstances and pollutants are removed from said second pretreatmentfloatation tub and said gas-liquid flotation tub based on a DissolvedOzone/Air flotation (DOF) step; an unreacted ozone second reuse step inwhich a gas containing unreacted ozone collected at an upper side of thesecond pretreatment floatation tub and the gas-liquid separationfloatation tub is pressurized along with a raw influent waste watersupplied from a raw influent waste water storing tub using a floatationpretreatment pressurizing pump and subjecting the raw influent wastewater and pressurized unreacted ozone from said second pretreatmentfloatation tub and said gas-liquid floatation tub to a firstpretreatment floatation tub and the waste water of the firstpretreatment floatation tub inputted from the raw influent waste waterstoring tub is treated in the first floatation tub based on the DOF stepthereby removing floating substances and pollutants from said firstfloatation pretreatment tub; and an ozone decomposition step whichdecomposes a remaining unreacted ozone discharged from the firstpretreatment flotation tub by an off-gas ozone removing apparatus,wherein said high pressure photo-oxidation decomposition reaction stepcomprises said pressure photo-oxidation decomposition reaction apparatusfor performing a photo-oxidation decomposition reaction step with a highpressure, said decomposition reaction apparatus includes a tube typehousing having a rectangular or circular cross section, and said housingis made of a stainless steel or titanium material, and a housing inletis connected with the photo-oxidation pressurizing pump and a housingdischarge port is connected with a treatment water feedback line and thegas-liquid separation floatation tub, and said decomposition reactionapparatus a crystal fixing unit is provided at an upper side of thehousing for accommodating an ultraviolet ray lamp in the interior of theupper side of the housing and for fixing at least one U-shaped crystaltube, and said at least one crystal tube is installed in the housing ina longitudinal direction of the housing, and a photocatalyst coatedsupporter is filled in an inner space between the at least one crystaltube and the housing, wherein said photocatalyst coated supportercomprises a stainless steel wire or a titanium wire having a diameter of0.1-5 mm is processed in a coil spring shape, said coil spring shape ofthe photocatalyst coated supporter is made in a hourglass shape, and thepitch of the spring is smaller than the diameter of the wire, and thepitch of the beginning and ending portions of the spring is near theneighboring pitch, so that the coil spring supporters are not overlappedwith each other, and in a sanding work step, the surfaces of the wiresare made by colliding sand or diamond sand with a high pressure air, andin a heat treatment step, the wire is coated and is heat-treated atbelow 800° C.
 2. A water treatment method, comprising: a pressurizingstep in which a waste water to be treated is pressurized with a highpressure by a photo-oxidation pressurizing pump along with an ozonegenerated by an ozone generator; a photo-oxidation decompositionreaction step in which a pollutant of the pressurized waste water isdecomposed based on a photo-oxidation reaction using a high pressurephoto-oxidation decomposition reaction apparatus; an unreacted ozonefirst reuse step in which a high pressure reaction effluent from thehigh pressure photo-oxidation reaction apparatus is inputted into both adownstream gas-liquid separation flotation tub and an upstream secondpretreatment floatation tub, and floating substances and pollutants areremoved from said second pretreatment floatation tub and said gas-liquidflotation tub based on a Dissolved Ozone/Air flotation (DOF) step; anunreacted ozone second reuse step in which a gas containing unreactedozone collected at an upper side of the second pretreatment floatationtub and the gas-liquid separation floatation tub is pressurized alongwith a raw influent waste water supplied from a raw influent waste waterstoring tub using a floatation pretreatment pressurizing pump andsubjecting the raw influent waste water and pressurized unreacted ozonefrom said second pretreatment floatation tub and said gas-liquidfloatation tub to a first pretreatment floatation tub and the wastewater of the first pretreatment floatation tub inputted from the rawinfluent waste water storing tub is treated in the first floatation tubbased on the DOF step thereby removing floating substances andpollutants from said first floatation pretreatment tub; and an ozonedecomposition step which decomposes a remaining unreacted ozonedischarged from the first pretreatment flotation tub by an off-gas ozoneremoving apparatus, wherein said off-gas ozone removing apparatuscomprises a photocatalyst decomposition step for decomposing andremoving said unreacted ozone based on a photo-oxidation decompositionreaction by employing a photocatalyst coated onto one selected from thegroup consisting of active charcoal, metallic net, and metallic coilspring wherein said photocatalyst are placed so as to surround anultraviolet lamp installed at a center of a stainless steel tube throughwhich the unreacted ozone passes and said ozone is irradiated by anultraviolet ray onto the photocatalyst.
 3. A water treatment method,comprising: a pressurizing step in which a waste water to be treated ispressurized with a high pressure by a photo-oxidation pressurizing pumpalong with an ozone generated by an ozone generator; a photo-oxidationdecomposition reaction step in which a pollutant of the pressurizedwaste water is decomposed based on a photo-oxidation reaction using ahigh pressure photo-oxidation decomposition reaction apparatus; anunreacted ozone first reuse step in which a high pressure reactioneffluent from the high pressure photo-oxidation reaction apparatus isinputted into both a downstream gas-liquid separation flotation tub andan upstream second pretreatment floatation tub, and floating substancesand pollutants are removed from said second pretreatment floatation tuband said gas-liquid flotation tub based on a Dissolved Ozone/Airflotation (DOF) step; an unreacted ozone second reuse step in which agas containing unreacted ozone collected at an upper side of the secondpretreatment floatation tub and the gas-liquid separation floatation tubis pressurized along with a raw influent waste water supplied from a rawinfluent waste water storing tub using a floatation pretreatmentpressurizing pump and subjecting the raw influent waste water andpressurized unreacted ozone from said second pretreatment floatation tuband said gas-liquid floatation tub to a first pretreatment floatationtub and the waste water of the first pretreatment floatation tubinputted from the raw influent waste water storing tub is treated in thefirst floatation tub based on the DOF step thereby removing floatingsubstances and pollutants from said first floatation pretreatment tub;and an ozone decomposition step which decomposes a remaining unreactedozone discharged from the first pretreatment flotation tub by an off-gasozone removing apparatus, wherein said high pressure photo-oxidationdecomposition reaction step comprises said pressure photo-oxidationdecomposition reaction apparatus for performing a photo-oxidationdecomposition reaction step with a high pressure, said decompositionreaction apparatus includes a tube type housing having a rectangular orcircular cross section, and said housing is made of a stainless steel ortitanium material, and a housing inlet is connected with thephoto-oxidation pressurizing pump and a housing discharge port isconnected with a treatment water feedback line and the gas-liquidseparation floatation tub, and said decomposition reaction apparatus acrystal fixing unit is provided at an upper side of the housing foraccommodating an ultraviolet ray lamp in the interior of the upper sideof the housing and for fixing at least one U-shaped crystal tube, andsaid at least one crystal tube is installed in the housing in alongitudinal direction of the housing, and a photocatalyst coatedsupporter is filled in an inner space between the at least one crystaltube and the housing, wherein said ultraviolet ray lamp is a lowpressure or high pressure Ag ultraviolet lamp which emits UV-C 254 nmwavelength or an intermediate ultraviolet ray lamp which emits aultraviolet ray of UV-A, B, C wavelengths, and a stabilizer system isinstalled for turning on the ultraviolet lamp with a single output orfor variably adjusting the output of the ultraviolet lamp by 5-120%,wherein said photocatalyst coated supporter comprises a stainless steelwire or a titanium wire having a diameter of 0.1-5 mm is processed in acoil spring shape, said coil spring shape of the photocatalyst coatedsupporter is made in a hourglass shape, and the pitch of the spring issmaller than the diameter of the wire, and the pitch of the beginningand ending portions of the spring is near the neighboring pitch, so thatthe coil spring supporters are not overlapped with each other, and in asanding work step, the surfaces of the wires are made by colliding sandor diamond sand with a high pressure air, and in a heat treatment step,the wire is coated and is heat-treated at below 800° C.